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Nutrition for Pregnancy

Healthy Beginnings – Understanding why nutrition in pregnancy and weight management matter

Thursday 3rd & 10th July 2025 | 1:00–2:00pm (BST)

To celebrate the launch our comprehensive insight Diet in Pregnancy briefing paper, the British Nutrition Foundation is pleased to announce an exciting webinar series.

 

Topics covered across the two sessions will include:

  • The latest evidence on gestational weight gain and its relationship to maternal and infant health;
  • The impact of maternal obesity and evidence-based strategies for supporting women;
  • Current dietary and supplementation recommendations during pregnancy;
  • Key nutrient deficiencies and challenges to achieving adequacy in the UK;
  • Opportunities for professionals to support pregnant women and to promote sustainable dietary patterns that meet nutritional needs during pregnancy.

The impact of nutrition in pregnancy on health

Pregnancy is an important life stage with many physiological changes and demands on your body to support a growing baby. Research shows that good nutrition before and during pregnancy is vitally important for your own wellbeing and your baby’s health. Not only during pregnancy, but also for your baby’s early and later life with consequences that could extend across generations.

 

But studies show that many women do not get enough of some key vitamins and minerals needed for a healthy pregnancy. So, if you are pregnant or trying for a baby, it is a great time to make sure that you are eating a healthy diet that provides all the essential nutrients for optimal fetal growth.

Healthy diet

A healthy diet before conception is key for optimising fertility and preparing the body for pregnancy. The ideal is to begin a pregnancy with good levels of all the nutrients that your body needs. You should eat a balanced diet and take folic acid supplements (ideally starting 3 months before trying to conceive) before trying for a baby.

 

Once pregnant, your nutritional needs change significantly to support both your growing baby and to maintain your own health. Your need key nutrients in the right amounts including:

Important nutrients for pregnancy

Scroll through the information below to find out more about some of the most important nutrients to support a healthy pregnancy.

Folic acid

This vitamin is particularly important before and during the first 12 weeks of pregnancy, when extra folic acid reduces the risk of neural tube defects, a type of birth defect that affects development of the baby’s spine.

 

Studies show that 83% of women aged 16 – 49 years had blood levels of folate that put them at increased risk of an NTD affected pregnancy.

 

If you are pregnant or trying for a baby you should take daily folic acid supplements (400 micrograms per day for most women). Ideally you should start taking folic acid 3 months before trying for a baby and continue for the first 12 weeks of pregnancy.

 

If you have a family history of neural tube defects, are taking anti-epileptic medication, or are diabetic, speak to your doctor as you may need a higher dose. 



Folate – the natural form of folic acid - is found in green leafy vegetables, wholegrains and wholegrain bread, nuts, peas, beetroot, oranges and berries. Eating plenty of folate-rich foods is also important during pregnancy.

Iron

It's common for women to develop iron deficiency during pregnancy. This is because your body needs extra iron to ensure your baby has a sufficient blood supply and receives necessary oxygen and nutrients. 

 

Over a third of all women aged 19 - 65 years in the UK have low iron intakes. Low iron status is linked to poor outcomes for both mother and baby, including premature birth and low birth weight

 

Try to build up your iron stores when you’re trying to become pregnant by eating a balanced diet including food containing iron, such as red meat, poultry and fish, beans, dark green leafy vegetables, nuts and wholegrains 

 

Vitamin C helps us absorb iron from plant sources. Try adding foods or drinks that are high in vitamin C (like peppers, tomatoes or a small glass of orange juice) to meals, to help increase your iron uptake. 

Omega 3s

As well as being a good source of vitamin D, oily fish is rich in omega-3 fatty acids, and this type of fat is needed for the development of your baby’s brain and eyes.

  

Eat at least one portion (140g, cooked weight) of oily fish per week. Fish is a healthy food to include and provides important nutrients for pregnancy. But limit fish to no more than two portions per week as some fish, including salmon, sea bass, sea bream, turbot, halibut and brown crab meat can be harmful if consumed in large amounts.  

 

If you are trying for a baby or are pregnant, avoid eating shark, swordfish and marlin, and more than four cans of tuna, or two fresh tuna steaks, a week. These fish can contain more mercury than other kinds of fish, which may harm your baby’s nervous system. 

 

Women are also advised to avoid ready-to-eat cold-smoked or cured fish products as they can present a risk of listeria.  

Iodine

Iodine is the mineral that enables the body to make thyroid hormones, which are needed for brain development. Low iodine levels during pregnancy can result in impaired infant brain development and have been linked with reduced reading age and IQ in childhood. 

 

Starting pregnancy with a good level of iodine may be as important to a baby’s long-term health as consuming enough iodine during pregnancy. But latest figures show that many women have insufficient levels of iodine and that there has been a decline in iodine status over the last decade.

 

Milk and dairy products are a main source of iodine for most people in the UK. So, if you don’t consume dairy foods, it is important to get iodine from alternative sources such as eggs, fish, shellfish, and iodine fortified milk alternatives. Iodine supplements are an option if you don’t consume iodine-rich foods, for example, if following a vegan diet.

Vitamin D

Vitamin D helps your body absorb calcium from your diet, which is important for healthy bones for you and your baby. 

 

Low levels of vitamin D are common in UK women, especially in winter. Women with darker skin and women who spend little time exposed to sunlight are most at risk of vitamin D deficiency. 

 

Oily fish is a good source of vitamin D and eating oily fish once a week (such as salmon, trout, mackerel, sardines, pilchards and herring) can make a useful contribution to your vitamin D intake. Vitamin D is also found in eggs and is added to some breakfast cereals and spreads. 

 

Because vitamin D is found only in a small number of foods, everyone, including pregnant and breastfeeding women, and women trying for a baby, should consider taking a daily supplement containing 10µg of vitamin D at least during the winter months. You may qualify for free vitamins via the government’s Healthy Start scheme

 

Do not take more than 100µg of vitamin D per day, as this could be harmful. 

 

Calcium for growth and development

Calcium is important for the growth and development of your baby’s bones and helps to maintain your bones as well.  Milk, cheese and yogurt are a good source of calcium so try to include low-fat versions in your diet.

 

Pregnant women are advised to avoid unpasteurised semi-hard and soft cheeses (unless cooked until steaming hot), all mould-ripened soft cheeses with a white coating on the outside, such as brie, camembert and chèvre (unless cooked until steaming hot), blue cheeses such as Danish Blue, Gorgonzola and Roquefort (unless cooked until steaming hot) and any unpasteurised milk or cream. 

 

Alternative sources of calcium include  

  • fortified plant-based milks and yogurts 
  • calcium-fortified breakfast cereals (check the label) 
  • some leafy green vegetables (such as kale, rocket and watercress)  
  • almonds, Brazil nuts, hazelnuts and sesame seeds 
  • bread that is not wholegrain (which are legally required to be fortified).  

Vegetarian and vegan diets during pregnancy

Balanced vegetarian and vegan diets have health benefits. But some nutrients that are important in pregnancy  can be more difficult to get from plant sources, including vitamin D, iodine, iron, calcium, and vitamin B12. 

 

To help get all the nutrients you need from a vegetarian or vegan diet you can:

 

  • Eat a diverse range of protein-rich foods, like tofu, beans, lentils and chickpeas, nuts, and eggs (for those who include them in their diet) milk, cheese and yogurt, or fortified plant-based alternatives .
  • Include fortified foods - such as breakfast cereals, dairy foods and plant-based milk alternatives. Look out for those that include vitamin D, iodine, iron, calcium, and vitamin B12.
  • Consider supplements - vitamin D supplement should be considered between October and March. Talk to your GP, pharmacist or midwife about whether you may need other vitamin or mineral supplements. Make sure supplements are suitable for pregnancy. 

To avoid or limit

Vitamin A

Large amounts of vitamin A can harm your unborn baby and may cause conditions such as spina bifida.  

 

Avoid supplements that contain vitamin A (including fish liver oil) and liver or liver products, such as pâté, which are high in vitamin A.

 

You can speak to your doctor or midwife for more information.  

Caffeine

Caffeine is found in coffee, tea, chocolate, sports/energy drinks, some soft drinks and some cold and flu remedies. It has been linked to an increased risk of your baby not growing as well as expected, so limit your caffeine intake when trying for a baby and while pregnant, to less than 200mg per day. This is roughly the amount in two mugs of instant coffee or two and a half cups of tea.  

 

Energy drinks are legally required to declare a high caffeine content and are not recommended for children or pregnant or breast-feeding women.  

Alcohol

The advice from the UK Chief Medical Officers’ is that, if you are pregnant or planning to become pregnant, the safest approach is not to drink alcohol at all to keep risks to your baby to a minimum. 

 

Drinking in pregnancy can lead to long-term harm to the baby, with the more you drink the greater the risk. 

 

The risk of harm to the baby is likely to be low if you have drunk only small amounts of alcohol before you knew you were pregnant or during pregnancy.  

 

If you who find out that you are pregnant after already having drunk during early pregnancy, avoid further drinking but be aware that it is unlikely in most cases that your baby has been affected. 

What is a healthy weight?

A body mass index (BMI) of between 18.5 and 25 is considered healthy. You can calculate your BMI here:  

 

Women who have too little body fat are more likely to have irregular periods or no periods at all, which can affect your ability to conceive.  

 

If you have suffered, or are suffering, from an eating disorder, gaining weight might be hard for you to manage. If this is the case, tell your doctor that putting on weight may raise difficult feelings for you. Extra support, such as counselling from a mental health professional, can help you cope with the challenges around eating healthily before and during your pregnancy. 

 

Having too much body fat can lower fertility, and women with excess body fat may not ovulate normally. Women with a BMI over 30 should seek advice from a health professional to help reduce weight before becoming pregnant.  

 

Very low-calorie diets and those that exclude a wide variety of foods or a whole food group, should be avoided as they can result in low intakes of important nutrients.  

 

If you are concerned about your weight in pregnancy, seek advice from your doctor or midwife.  

 

What is a healthy weight during pregnancy?

Weight gain varies greatly in pregnancy. Most pregnant women gain between 10kg and 12.5kg (22lb to 28lb) putting on most of the weight after week 20.

 

Gaining too much weight can increase your risk of complications, including gestational diabetes, pre-eclampsia (high blood pressure) and the need for a caesarean delivery.  

 

Dieting during pregnancy is not recommended as it may harm your baby’s health.  

Eating for two?

Energy requirements during the first and second trimester are no different to normal as your body makes some adaptations to help reduce the extra energy it might otherwise need.

 

In the last 12 weeks of pregnancy, you do need a little extra energy – about 200kcal more per day.

 

Good sources of extra calories include steamed vegetables, egg noodles, a small handful of unsalted nuts, porridge with a spoonful of raisins, or wholegrain toast with peanut better.  

 

Morning sickness

Morning sickness is a normal part of pregnancy; it usually settles in the second trimester and is unlikely to cause longer-term problems.  

 

Some women find eating carbohydrate-rich foods helps reduce nausea and eating small amounts throughout the day may also help. There is some evidence that ginger products, such as fresh ginger or ginger teas, help reduce nausea and vomiting in pregnancy.

 

Try to replace the fluids that are lost when you are sick.  

 

Some women experience severe nausea and vomiting during pregnancy (‘hyperemesis gravidarum’) and should consult their doctor or midwife. 

 

Breastfeeding

For breastfeeding women, losing weight by eating healthily and taking regular exercise will not affect the quantity or quality of their milk. 

 

Women who exclusively breastfeed may require extra calories, but your body will also use up the fat stored during pregnancy for this exact purpose.  

 

Exclusively breastfeeding is linked to greater weight loss after pregnancy and breastfeeding for a longer period is associated with a healthier BMI in the long term. Breastfeeding has important health benefits for mother and baby, including supporting your baby’s immune system. 

Foods to avoid in pregnancy

Which foods and drinks do I need to avoid when I'm pregnant, and why?

It is important to eat a healthy, balanced diet when you are pregnant, not only to help your baby grow healthily and give them the best start in life but also to help you feel your best too.

 

Some foods are best avoided in pregnancy, however.  

Soft cheese

Avoid soft cheeses with white rinds such as brie, camembert and others with a similar rind, including goats' cheese with a rind (sometimes known as chèvre) 

 

Also, avoid soft, blue-veined cheeses such as Danish blue, gorgonzola and Roquefort 

 

These cheeses can contain listeria bacteria that cause listeriosis. Listeriosis is an infection that can cause flu-like symptoms. Although listeriosis is extremely serious in pregnancy, it is very rare. 

Unpasteurised milk or cream

Pasteurisation is a heat treatment process to kill bacteria and prevent food poisoning. 

 

Unpasteurised or ‘raw’ milk and cream (from cows’, goats’ or sheep) are often sold at farmers markets and farm shops. They may contain harmful bacteria that could cause food poisoning and should be avoided.

  

These products must carry an on-pack warning in England and Wales. The sale of raw milk is banned in Scotland.  

Raw meat

Including raw cured meats, for example Parma ham (prosciutto), chorizo, pepperoni and salami 

 

Many cold meats such as salami, pepperoni, chorizo and Parma ham, are cured and fermented but not cooked, and there is a risk they contain toxoplasmosis-causing parasites.

 

Freezing for four days or more makes the meat safer to eat, as does cooking (pepperoni on a pizza, for example).  

Hydration

Water is needed to produce the fluid surrounding your baby and to help increase your blood volume, so it’s important to stay hydrated during pregnancy.  

 

Signs of dehydration include dark urine, dizziness, headaches, tiredness or a dry mouth 

What (not) to drink

Water

Tap water is a good choice, but all non-alcoholic drinks can count towards your fluid intake, including milk, fruit and vegetable juices, smoothies and hot drinks.

Caffeine

Keep your caffeine below 200mg per day during pregnancy. A mug of instant coffee, for example, has about 100mg of caffeine, filter coffee about 140mg, and a mug of tea about 75mg. Bear in mind that green tea has caffeine.  

Sugary drinks

There is a greater risk of tooth decay and gum disease in pregnancy, so limit sugary and acidic drinks as fizzy soft drinks, sweetened iced teas, juices and smoothies, to mealtimes only.  

How to replace nutrients found in animal foods

Ramadan and pregnancy

If you are a Muslim woman who is pregnant, or is planning to become pregnant, you may be wondering whether you should still fast during Ramadan.

 

Islamic law gives permission for pregnant and breastfeeding women to opt out of fasting if she fears that it will harm her health or the health of her baby.



Find out more on our pages on Ramadan and pregnancy.

Physical activity in pregnancy FAQs

It is well known that regular physical activity can help to reduce the risk amongst other things of high blood pressure and type 2 diabetes.

 

In pregnancy, being active can also help reduce varicose veins, swelling in the feet and legs and improve lower back pain, and there is some evidence to suggest that women who exercise during pregnancy have shorter labours and fewer delivery complications than those who do not. 

If you have not been used to exercise, start gradually with 10 minute bouts of moderate exercise, building up to a total of 150 minutes, spread throughout the week. 

 

‘Moderate’ activity is any activity that makes you breathe faster but still be able to hold a conversation.  

 

Pregnancy can affect your ability to do physical activity and as a general rule, if you feel uncomfortable, stop and seek advice from your doctor or midwife, and always consult with them before embarking on a new exercise regime. There is helpful information here

To avoid hitting your bump, refrain from contact sports and sports that risks falls such as:

  • horse-riding
  • skiing
  • ice skating
  • cycling

Also, avoid scuba diving as the change in pressure may not be good for your baby and avoid exertion at high altitudes (over 2500m) until you have acclimatised, which may take a few days. 

Do not exercise in hot humid conditions, as you are more likely to get too hot during exercise when you are pregnant, which can be dangerous for your baby. 

 

Keep well hydrated during exercise. Make sure you drink before, during and after exercise. 

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Please note that advice provided on our website about nutrition and health is general in nature. We do not provide any individualised advice on prevention, treatment and management for patients or their family members.